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landlordy's avatar
landlordy
Explorer
Jan 01, 2018

House Battery Charge Question

I have a house bank with two 12 volt batteries in parallel. I read that I should not let them fall below 50% charge when boondocking, but I forgot how to calculate what a 50% charge with this setup can be. Currently they are at 12.5, and the string of Christmas lights I have is making me nervous. Thanks and happy new year!
  • gbopp's avatar
    gbopp
    Explorer
    Jan 01, 2018
    Google: The 12 Volt Side of Life. It will have a chart showing the voltage and state of charge.
    Sorry, I can't make a link on my Kindle.
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Jan 01, 2018
    Fifty percent is not an absolute. You can use a battery to any depth of discharge you desire but the lower you go the fewer cycles that battery will provide. So if you discharge regularly to 80% you’ll get about 500 cycles. See...

    https://www.google.com/search?q=rv+battery+depth+of+discharge+cycle+chart&ie=UTF-8&oe=UTF-8&hl=en-us&client=safari#imgrc=3njorLpSGIaVAM:
  • wildtoad's avatar
    wildtoad
    Explorer II
    Jan 01, 2018
    Based on a chart I saw after doing a search, you are about 85%. 12.2 volts would be about 50%.

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